[PATCH 1/3] include: fb: Add definiton for window positioning structure

[Baruch Siach]

Hi Ajay,

On Tue, Sep 20, 2011 at 08:56:57PM +0530, Ajay kumar wrote:
> Hi Baruch,
> On Tue, Sep 20, 2011 at 4:54 PM, Baruch Siach <baruch at tkos.co.il> wrote:
> > Hi Ajay,
> >
> > On Tue, Sep 20, 2011 at 11:30:39AM -0400, Ajay Kumar wrote:
> >> This patch adds a data structure definiton to hold framebuffer windows/planes.
> >> An ioctl number is also added to provide user access
> >> to change window position dynamically.
> >
> > [snip]
> >
> >> +/* Window overlaying */
> >> +struct fb_overlay_win_pos {
> >> +     __u32 win_pos_x;        /* x-offset from LCD(0,0) where window starts */
> >> +     __u32 win_pos_y;        /* y-offset from LCD(0,0) where window starts */
> >> +};
> >
> > Why not allow negative offsets where the left or upper part of the framebuffer
> > is hidden?
> 
> Thanks for pointing it out. Are there drivers which place the overlay
> windows such that some part of the window is hidden from being
> displayed on the screen?

I don't know. However, since this is new userspace ABI which should stay 
compatible forever, we should make sure to do it right. Using __s32 instead of 
__u32 won't limit us in the future.

baruch

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